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This article mainly introduces how to use Java annotations and reflection to achieve Junit4 call related knowledge, the content is detailed and easy to understand, the operation is simple and fast, with a certain reference value, I believe you will get something after reading this article on how to use Java annotations and reflection to achieve Junit4 calls, let's take a look.

Case requirement

Requirements: simulate the use case structure in Junit4 and customize a label as the identification of the test case.

Annotate @ Test in Junit4 to represent test cases. The essence of each test case is a method in the test class, that is:

@ Test public void test () {fail ("Not yet implemented");}

Specific requirements:

The test class is the default constructor

Use the label MyTag to identify whether the method is a use case or not

The method as a use case must have no parameters

Write a method runCase (String pkgName) to complete the call to the test case in the specified class

Annotation design

First, you need to define an annotation MyTag with the following code:

Import java.lang.annotation.Retention; import java.lang.annotation.Target; import java.lang.annotation.ElementType; import java.lang.annotation.RetentionPolicy; @ Retention (RetentionPolicy.RUNTIME) @ Target (ElementType.METHOD) public @ interface MyTag {String name ();} Test case Design

Simulate the junit4 framework and write a test class, where login, info, and logout are nonparametric methods, while test is a parameterized method

Public class TestTag {@ MyTag (name= "case1") public void login () {System.out.println ("login");} @ MyTag (name= "case2") public void info () {System.out.println ("info");} @ MyTag (name= "case3") public void logout () {System.out.println ("logout");} @ MyTag (name= "case4") public void test (String p) {System.out.println ("logout");}} Design ideas for runtime classes

Because the test class is the default constructor, instantiate the class using the following API

Class clazz = Class.forName (pkgName) Object obj = clazz.newInstance ()

Because there are many methods in the test class, we need to get all the methods and filter them according to the rules, as follows:

Method [] methods = clazz.getMethods (); for (Method method: methods) {/ / filter rules}

Determine whether the label of the method is MyTag. The code is as follows:

If (method.getAnnotation (MyTag.class)! = null)

To determine whether the method has no parameters, the code is as follows:

If (method.getParameterCount () = = 0)

Run the method with the following code:

Method.invoke (obj) complete code public static void runCase (String pkgName) throws IllegalAccessException,IllegalArgumentException, InvocationTargetException, InstantiationException,ClassNotFoundException {Class clazz = Class.forName (pkgName); Object obj = clazz.newInstance (); Method [] methods = clazz.getMethods (); for (Method method: methods) {if (method.getAnnotation (MyTag.class)! = null&& method.getParameterCount () = 0) {method.invoke (obj) / / call method System.out.println ("Test case name is:" + method.getName ());}

Run the code and the output is as follows:

Logout

The test case name is: logout

Login

The test case name is: login

Info

The test case name is: info

This is the end of the article on "how to use Java annotations and reflection to implement Junit4 calls". Thank you for reading! I believe you all have some knowledge of "how to use Java annotations and reflection to achieve Junit4 calls". If you want to learn more, you are welcome to follow the industry information channel.

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